Advancements in human gene therapy depend to a large degree on the development of delivery systems capable of the efficient introduction of the genetic material into the target cell. The experiments proposed in this application are designed to evaluate the potential advantage of a new synthetic methodology, namely the genetic engineering of polymers (as gene carriers), of the complexation behavior of cationic copolymers of amino acids with DNA, and their corresponding transfection efficiency. Through sequence-specific design, this technology provides a unique means to synthesize biopolymers with sell defined properties such as charge periodicity, molecular weight, and three dimensional structure, and allows for the precise introduction of of informational peptide sequences along the polymeric backbone. The broad long-term objective of this research is to develop novel genetically engineered polymers for gene delivery. The specific aims are: 1. To examine the effect of synthetic methodology on the alpha-helical content of a series of model cationic copolymers of arginine, lysine, serine, and alanine, and on polymer DNA complexation and transfection efficiency. Random copolymers will be compared with their genetically engineered counterparts. 2. To examine the effect of discrete molecular weight changes on polymer-DNA complexation and transfection efficiency. A series of monodisperse copolymers of lysine and serine with varying molecular weights will be genetically engineered and their complexation with DNA and transfection efficiency will be evaluated. 3. To examine the effect of charge density and charge periodicity; random copolymers of lysine, and alanine will be compared with genetically engineered counterparts. 4. To study the effect of location of GALA as a model membrane destabilizing agent along the polymer chain on transfection efficiency. Results from these studies may pave the way for new polymer-DNA constructs where with a high degreee of precision, it may be possible to tailor-make polymeric gene carriers with an improved transfection efficiency.